| 摘要 |
<p>A method for operating a digital in - analogue out radio frequency amplifier, further referred to as DARFA (50),
wherein a digital input signal (53) is processed in a digital signal processing unit, further referred to as DSP unit (51), generating a processed digital baseband signal (54) out of the digital input signal (53),
wherein an analogue RF input signal (24) with a non-constant envelope is generated out of the processed digital baseband signal (54),
wherein the analogue RF input signal (24) is fed into an RF power amplifier (22) which generates an amplified analogue RF output signal (26) out of the analogue RF input signal (24),
wherein the RF power amplifier (22) receives a supply voltage (27a) from a modulator unit (21),
wherein the modulator unit (21) comprises a linear amplifier stage (33) and a switching amplifier stage (38), whose outputs (36, 37) are combined to one common modulator output (28) providing the supply voltage (27a) and supply current,
and wherein the input (30) of the linear amplifier stage (33) is fed with an analogue input signal (29) corresponding to the envelope of the processed digital baseband signal (54),
is characterized in that the switching amplifier stage (38) is controlled by means of a pulse width modulated signal (44) generated within the DSP unit (51),
wherein the pulse width modulated signal (44) is derived digitally from the partially or completely processed digital baseband signal (54). The invention provides a method for operating a DARFA which allows a higher accuracy in the control of the RF power amplifier.</p> |
